CHARACTERIZATION AND SPECIES RECOGNITION OF LACTOBACILLUS-PLANTARUM STRAINS BY RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM (RFLP) OF THE 16S RIBOSOMAL-RNA GENE

Twenty-one strains, labelled Lactobacillus plantarum or Lact. plantaru m-like, and isolated from different natural sources, were characterize d by restriction fragment length polymorphism (RFLP) of the 16S rRNA g ene using HindIII and EcoRI cleaved chromosomal DNA, together with Lac t. plantarum ATCC 14917(T), Lact. pentosus ATCC 8041(T), Lact. plantar um ATCC 10776 and Lact. plantarum ATCC 8014. The fermentation patterns on API 50CH were recorded at 30 degrees C and 37 degrees C for all st rains. The phenotypes nlere heterogeneous, and the ability to ferment 17 of the 49 carbohydrates varied. The fermentation of some carbohydra tes, for example D-raffinose and D-arabitol, was temperature-dependent . Strains having identical API profiles were separated by the plasmid profile. All strains but one (affiliated to Lact. casei) had identical 16S ribosomal DNA sequences (Lact. plantarum/Lact. pentosus). The RFL P study resulted in identical ribopatterns for 17 of the strains, incl uding the type strain of Lact. plantarum (pattern A1). Four strains ha d related fragment patterns to that of Lact. plantarum sensu stricto; three of these strains had more than 60% DNA:DNA homology to the type strain of Lact. plantarum, and one had less than 50% DNA:DNA homology to Lact. plantarum ATCC 14917(T). Two strains had fragment patterns si milar to the type strain of Lact. pentosus, and they had more than 80% DNA:DNA homology to Lact. pentosus ATCC 8041(T). One of the Lact. pen tosus strains shared one band with the A1 pattern. The ribopatterns of Lact. plantarum were homogeneous (identical for 85% of the strains), irrespective of phenotype and source of isolation. RFLP of the 16S rRN A genes using EcoRI and HindIII might be used for species recognition of Lact. plantarum, but, but seems less suitable for strain typing.